Filter mounts for a portable fan and methods for mounting a filter to a portable fan

ABSTRACT

A filter frame is removably attachable to a box fan. The filter frame is adapted for receiving a standard HVAC-style filter for removing contaminants from air flow induced by the fan. In this manner, a cost-effective means for filtering a flow of air is provided for residential and commercial settings. The filter frame is adaptable to a variety of standard box fan types of different styles and dimensions. The frame is configured to accommodate standard filters, such as those readily available from retail hardware stores and home centers.

RELATED APPLICATIONS

This application is a continuation application of U.S. application Ser.No. 13/713,756, filed Dec. 13, 2012, now U.S. Pat. No. 8,591,619, whichis a continuation application of U.S. application Ser. No. 13/403,362,filed on Feb. 23, 2012, now U.S. Pat. No. 8,349,047, which is acontinuation application of U.S. application Ser. No. 13/022,921, filedFeb. 8, 2011, now U.S. Pat. No. 8,137,426, which is a continuation ofU.S. application Ser. No. 12/691,219, filed on Jan. 21, 2010, now U.S.Pat. No. 7,905,938, which is a continuation application of U.S.application Ser. No. 11/344,749, filed Feb. 1, 2006, now U.S. Pat. No.7,670,401, which claims the benefit of U.S. Provisional Application Ser.No. 60/648,892, filed Feb. 1, 2005, U.S. Provisional Application Ser.No. 60/661,529 filed Mar. 14, 2005, and U.S. Provisional ApplicationSer. No. 60/737,190, filed Nov. 16, 2005, the contents of each of whichare incorporated herein by reference, in their entirety.

BACKGROUND OF THE INVENTION

Portable fans, such as box fans, are popular as a cost-efficient meansfor cooling or ventilating interior areas of commercial and residentialbuildings. Box fans are inexpensive, light, and portable, and can beeasily repositioned to provide a desired interior air flow.

Filters have been applied to box fans as a means for removing air-bornecontaminants from the air flow. A number of mounting configurations havebeen devised that secure a filter to a box fan. U.S. Design Pat. No. DES377,390 discloses a filter mount that is incorporated within the body ofa box fan. This configuration requires a specialized fan chassis, andtherefore is not applicable to general-purpose box fans. U.S. Pat. No.4,781,526 discloses a filter mount that is affixed to an exteriorportion of a fan body. In this configuration, the filter bracket ispermanently affixed to holes formed in the fan body using specializedmounting hardware, such as machine screws. U.S. Pat. No. 6,527,838discloses a filter mount including a plurality of brackets that adhereto a side surface of the fan. The brackets are permanently affixed tothe fan, and take the form of specialized hardware, which, when mountedto a particular fan body, cannot be re-used on another fan. Inalternative embodiments disclosed in the U.S. Pat. No. 6,527,838 patent,a filter bracket is applied to a fan body using hook and loop fastenersor screws about a periphery of the body of the fan. Again, suchspecialized attachment hardware is semi-permanent, can disfigure the fanbody, and cannot be re-used on another fan.

SUMMARY OF THE INVENTION

The present invention is directed to a filter mount for a box fan. Afilter mount in the form of a frame is removably mountable to a fanchassis and does not cause any permanent disfigurement to the fan body.The filter frame is adapted and shaped to receive a standard air filter,such as the type of filter commonly used in residential heating systems.The filter and frame are preferably sized to closely match, and cover, astandard-sized fan grill at the input or output face of the fan, so thata substantial amount of air flow passes through the filter.

The filter frame is preferably sized to have a narrow profile so as notto inhibit the air flow induced by the fan. In one embodiment, strapsare provided to secure the frame to the fan body, such that the frame isreadily removable. In one embodiment, the straps comprise elastic bands.Tension in the elastic bands, when mounted, secures the filter frame tothe fan chassis. The elastic bands are optionally adjustable in lengthso that the filter frame is compatible with a variety of fan chassistypes and a variety of fan chassis thicknesses.

In another embodiment, the frame includes features that attach to agrill of a fan, for example, features that mate with one or more grillapertures. The frame can include, for example rigid pegs or hooks thatare inserted in one or more grill apertures at one of a top and bottomof the fan grill, and spring-loaded hooks that are inserted in one ormore grill apertures at the other of the top and bottom of the fan grillto secure the frame in place against the fan grill.

In another embodiment, a filter frame can be integrated directly intothe grill of the fan. In this embodiment, the fan grill can be formed ina molding process to include integral filter guides at left side, rightside, and bottom side portions of the fan grill. In this manner, the fangrill includes an integral filter frame that can accept standard-sizedfilters.

In this manner, a cost-effective means for filtering a flow of air isprovided for residential and commercial settings. The filter frame isadaptable to a variety of standard box fan types of different styles anddimensions. The frame is configured to accommodate standard filters,such as those readily available from retail hardware stores and homecenters.

In one embodiment, the filter frame includes one or more elastic bands,or bungy cords. Each elastic band is attached at a first end to one ofthe side members of the filter frame. A second end of each elastic bandincludes a hook that is adapted to attach to one of the front and reargrills of the fan, or other feature of the fan. The frame is mounted toone face of the fan body, and the elastic band or bands stretch aboutthe sides of the fan to the other face of the fan body. The hooksoperate in conjunction with the tension in the stretched band or bandsto secure the filter frame to the fan body.

In one embodiment, a single pair of bands is employed, one bandinterfacing with each respective left and right side member of the frameat or near a central position of the side members. In someconfigurations, a single pair of bands is sufficient for securing theframe to the fan body. In another embodiment, where additional securingforce is required, multiple pairs of bands are employed, each band ofeach pair interfacing with a left or right side member at top and bottomregions of the side members.

The elastic bands may be permanently attached to the frame, for example,by rivets or screws, or by tying the bands to the frame. Alternatively,the elastic bands are removable from the frame, for example, by hooks,buttons, loops, or other attachment mechanisms. One end, or both ends,of each elastic band can be removably or permanently attached to theframe.

In an embodiment where both ends of each elastic band attach to theframe, one or more of the bands loop around the fan body, for exampleover the top, bottom, left and/or right sides of the fan body, to securethe frame to the fan body. As mentioned above, the ends of each elasticband may be permanently or removably attached to the frame.

In an embodiment where a first end of each elastic band is attached tothe frame, the second end includes a hook for attaching the elastic bandto a feature of the fan chassis, for example, a fan grill, handle, orother feature. In another embodiment, elastic bands from left and rightsides of the frame each include hooks, or other clasping features, suchthat the second ends of paired elastic bands can be coupled to eachother to form one large band that extends about the fan chassis. Inanother embodiment, the frame includes pegs that extend from the frameand extend between adjacent cross members of the rear or front grill ofthe fan, such that the pegs prevent the frame from shifting or slidingrelative to the cross members.

In another embodiment, the filter frame includes mounting knobs atspaced-apart coupling locations, and the elastic bands each include anarray of holes at first ends of the bands. The holes of the elasticbands mate with the coupling knobs as a convenient mechanism forremovably attaching the elastic bands to the filter frame. The secondends of the elastic bands may include hooks, as described above, forattaching to a fan chassis feature. Alternatively, the elastic bandsinclude an array of holes at both ends, and the bands stretch about thebody of the chassis, and couple to both sides of the frame. The mountingknobs secure the bands, and retain the elastic bands in a tensionedstate, securing the filter frame to the fan. The array of holes aredistributed along the length of the end of each band to allow foradjustment in the length of the elastic band. In this manner, the filterframe is adapted to accommodate fan bodies of different thicknesses.

In another embodiment, the filter frame is secured to the fan chassis byelongated bolts that extend through the body of the fan. Holes areincluded in the frame to receive the bolts. The holes are preferablyelongated to allow for play in positioning the frame relative to the fanbody, so that the frame is compatible with different fan grillconfigurations. The elongated bolts are secured to the filter frame andfan with washers and wing nuts, which, when tensioned, retain the filterframe against the body of the fan. The bolts are configured so as toavoid interference with fan operation.

In another embodiment, the filter frame is secured to the fan chassisusing fasteners that are bolted to the frame. In one embodiment, thefastener is inserted into the fan grill in a horizontal position betweencross members of the rear or front grill of the fan, and is then rotatedto a vertical position and tightened in place to affix the filter frameto the fan. The fastener is sized to accommodate a range of fan grillconfigurations.

In an alternative embodiment, the frame is attached to the rear or frontgrill of a fan with standard cable ties.

In another embodiment, the filter frame is unitary and formed in amolding process, for example in a straight-pull injection moldingprocess.

In another embodiment, the filter frame is adapted to receive multiplefilters.

In another embodiment, the filter frame is unitary and formed in amolding process and includes spring-loaded hooks for securing the filterframe to the grill of the fan.

In another embodiment, the filter frame is integral with the front orrear grill of the fan body. The filter frame is molded on an outerportion of the front or rear grill, the filter frame and the front orrear grill being unitary.

In one aspect, the present invention is directed to a removable filterframe for a fan. A frame body includes opposed first and second sidechannels. Each of the first and second side channels has a longitudinalaxis and the first and second side channels define a slot for insertionof an air filter. The slot has an upper end that allows for insertionand removal of an air filter, and a lower end that includes a stop forrestricting further movement of an inserted air filter. The removablefilter frame further comprises a coupler that extends from the framebody in a direction transverse to the longitudinal axes of the first andsecond side channels. The coupler is constructed and arranged to couplethe frame body to a grill of a fan.

In one embodiment, the frame body is unitary. Further, in anotherembodiment, the frame body is formed in a straight-pull injectionmolding process.

In another embodiment, the first and second side channels of the framebody are formed as separate units that are mounted together.

In another embodiment, the frame body further includes at least onecross member between the first and second side channels that providesfor lateral rigidity to the frame body.

In another embodiment the first and second side channels each comprise aside surface of the frame body and tabs that extend from the frame bodyin a horizontal direction to define the first and second side channels.

In another embodiment, the stop is positioned at a bottom of at leastone of the first and second side channels. In another embodiment, thestop comprises a portion of the frame body that extends in a horizontaldirection between the longitudinal axes of the first and second sidechannels. Further, in another embodiment, the stop comprises ahorizontal channel extending in the horizontal direction between bottomportions of the first and second side channels.

In another embodiment, the coupler comprises at least one tab thatextends from the frame body and is constructed and arranged to couplethe frame body to a grate of a grill of a fan.

In another embodiment, the coupler comprises at least one hook thatextends from the frame body and is constructed and arranged to couplethe frame body to a grate of a grill of a fan.

In another embodiment, the at least one hook is spring-loaded.

In another embodiment, the coupler comprises one of multiple fasteners,multiple elongated bolts, and multiple cable ties that extend from theframe body and are constructed and arranged to couple the frame body toa grate of a grill of a fan.

In another embodiment, the removable filter frame further compriseselastic bands that are coupled to the frame body and are constructed andarranged to couple about a chassis of a fan.

In another embodiment, the removable filter frame further comprises afoam pad coupled between the frame body and a grill of a fan.

In another embodiment, the first side channel and the second sidechannel are constructed to have a depth such that multiple filters canbe inserted in the frame body.

In another aspect, the present invention is directed to a removablefilter frame for a fan. A frame body includes opposed first and secondside channels. The first and second side channels define a slot forinsertion of an air filter. The slot has an upper end that allows forinsertion and removal of an air filter, and a lower end that includes astop for restricting further movement of an inserted air filter. Atleast one elastic band is coupled to the frame body, the at least oneelastic band is constructed and arranged to extend about a portion of afan chassis so that when installed, tension in the at least one elasticband operates to secure the frame body to a fan.

In one embodiment, the frame body is unitary.

In another embodiment, the frame body is formed in a straight-pullinjection molding process.

In another embodiment the first and second side channels of the framebody are formed as separate units that are mounted together.

In another embodiment, the frame body further includes at least onecross member between the first and second side channels that provideslateral rigidity to the frame body.

In another embodiment, the first and second side channels each comprisea side surface of the frame body and tabs that extend from the framebody in a horizontal direction to define the first and second sidechannels.

In another embodiment, the stop is positioned at a bottom of at leastone of the first and second side channels. In another embodiment, thestop further comprises a portion of the frame body that extends in ahorizontal direction between the first and second side channels. Inanother embodiment, the stop comprises a horizontal channel extending inthe horizontal direction between bottom portions of the first and secondside channels.

In another embodiment, the at least one elastic band comprises aplurality of elastic bands, each coupled at both ends to the frame body.

In another embodiment, the at least one elastic band comprises aplurality of elastic bands, each coupled at one end to the frame body.

In another embodiment, each of the elastic bands of the plurality ofelastic bands further comprises a hook at at least one end. The hook isconstructed and arranged to couple the frame body to a grate of a grillof a fan.

In another embodiment, each of the elastic bands of the plurality ofelastic bands comprises a hook at a first end and a plurality of holesat a second end and the frame body further comprises knobs. Theplurality of holes at the second end of each of the plurality of elasticbands is adapted to mate with one of the knobs to define a length ofeach of the elastic bands between the knob of the frame body and thehook.

In another embodiment, the at least one elastic band is removablycoupled at at least one end to the frame body.

In another embodiment, the at least one elastic band is fixed at atleast one end to the frame body.

In another embodiment, the first and second side channels areconstructed to have a depth such that multiple filters inserted in theframe body.

In another embodiment, the removable filter frame further comprises acoupler extending from the frame body in a direction transverse tolongitudinal axes of the first and second side channels. The coupler isconstructed and arranged to couple the frame body to a grill of a fan.

In another embodiment, the coupler comprises at least one tab thatextends from the frame body and is constructed and arranged to couplethe frame body to a grate of a grill of a fan.

In another embodiment, the coupler comprises at least one hook thatextends from the frame body and is constructed and arranged to couplethe frame body to a grate of a grill of a fan.

In another embodiment, the at least one hook is spring-loaded.

In another embodiment, the coupler comprises one of multiple fasteners,multiple elongated bolts, and multiple cable ties that extend from theframe body and are constructed and arranged to couple the frame body toa grate of a grill of a fan.

In another aspect, the present invention is directed to grill for a fan.A latticed grate includes cross members and openings and has an innersurface and an outer surface. Retaining members extend from the outersurface of the grate in a direction transverse to the outer surface atfirst and second outer regions of the grill to define opposed first andsecond side channels. The first and second side channels define a slotfor insertion of an air filter. The slot has an upper end that allowsfor insertion and removal of an air filter, and a lower end thatincludes a stop for restricting further movement of an inserted airfilter.

In one embodiment, the grate and the retaining members are formed in amolding process so that they are unitary. In another embodiment, thegrate and the retaining members are formed in a straight-pull injectionmolding process.

In another embodiment, the retaining members are L-shaped. A firstportion of each retaining member extends from the outer surface in adirection transverse to the outer surface and a second portion of eachretaining member extends from the first portion of the retaining memberin a direction substantially parallel to the outer surface and toward amiddle region of the grate.

In another embodiment, the stop is L-shaped. A first portion of the stopextends from the outer surface in a direction transverse to the outersurface and a second portion of the stop extends from the first portionof the stop in a direction substantially parallel to the outer surfaceand toward a middle region of the grate.

In another embodiment, the stop is integrated into the retaining membersat a low end of the slot.

In another embodiment, each of the first and second side channelsincludes multiple retaining members.

In another embodiment, each of the first and second side channelsincludes a single retaining member.

In another embodiment, the stop comprises multiple stops.

In another aspect, the present invention is directed to a fan. The fanincludes fan blades and a motor that operates the fan blades. A fanchassis surrounds the motor and fan blades. Front and rear grills shieldthe fan blades and allow for air movement through the fan. Each of thefront and rear grills includes a latticed grate having cross members andopenings and has an inner surface and an outer surface. Retainingmembers extend from the outer surface of the grate of at least one ofthe front and rear grills in a direction transverse to the outer surfaceat first and second outer regions to define opposed first and secondside channels. The first and second side channels define a slot forinsertion of an air filter. The slot has an upper end that allows forinsertion and removal of an air filter, and a lower end that includes astop for restricting further movement of an inserted air filter.

In one embodiment the grate and the retaining members are formed in amolding process so that they are unitary.

In another aspect, the present invention is directed to a method ofmounting a filter to a fan. The method includes coupling a frame bodyhaving opposed first and second side channels, each of the first andsecond side channels having a longitudinal axis, to a grill of a fan bycouplers extending from the frame body in a direction transverse to thelongitudinal axes of the first and second side channels. The couplersengage a grate of the grill through an opening in the grate. The firstand second side channels define a slot for insertion of an air filter.The slot has an upper end that allows for insertion and removal of anair filter, and a lower end that includes a stop for restricting furthermovement of an inserted air filter. An air filter is inserted into anupper end of the slot.

In one embodiment, coupling the frame body to the grill of the fanfurther comprises coupling the frame body to a grate of the grill of thefan using at least one tab extending from the frame body.

In another embodiment, coupling the frame body to the grill of the fanfurther comprises coupling the frame body to a grate of the grill of thefan using at least one hook extending from the frame body. In anotherembodiment, the at least one hook is spring-loaded.

In another aspect, the present invention is directed to a method ofmounting a filter to a fan. The method comprises coupling a frame bodyhaving opposed first and second side channels to a grill of a fan by atleast one elastic band extending about a portion of a fan chassis sothat when installed, tension in the at least one elastic band operatesto secure the frame body to a fan. The first and second channels definea slot for insertion of an air filter. The slot has an upper end thatallows for insertion and removal of an air filter, and a lower end thatincludes a stop for restricting further movement of an inserted airfilter. An air filter is inserted into an upper end of the slot.

In another aspect, the present invention is directed to a method thatcomprises forming a grill for a fan including a latticed grate includingcross members and openings and having an inner surface and an outersurface. The method further comprises forming retaining members thatextend from the outer surface of the grate in a direction transverse tothe outer surface at first and second outer regions of the grill todefine opposed first and second side channels. The first and second sidechannels define a slot for insertion of an air filter. The slot has anupper end that allows for insertion and removal of an air filter, and alower end that includes a stop for restricting further movement of aninserted air filter. The method further comprises mounting the grill toa fan chassis.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features and advantages of theinvention will be apparent from the more particular description ofpreferred embodiments of the invention, as illustrated in theaccompanying drawings in which like reference characters refer to thesame parts throughout the different views. The drawings are notnecessarily to scale, emphasis instead being placed upon illustratingthe principles of the invention.

FIGS. 1A and 1B are perspective views of an embodiment of the presentinvention. FIG. 1A is a perspective view of a filter frame includingelastic bands and FIG. 1B is a perspective view of the filter frame ofFIG. 1A attached to a box fan, in accordance with the present invention.

FIGS. 2A-2D are perspective views of another embodiment of the presentinvention. FIG. 2A is a perspective view of an elastic band including anarray of holes. FIG. 2B is a perspective view of the elastic bands ofFIG. 2A attached to a box fan. FIG. 2C is a perspective view of a filterframe including mounting knobs. FIG. 2D is a perspective view of thefilter frame of FIG. 2C attached to the box fan of FIG. 2B by theelastic bands of FIG. 2A, in accordance with the present invention.

FIGS. 3A and 3B are perspective views of another embodiment of thepresent invention. FIG. 3A is a perspective view of a filter frameattachable to a box fan using elastic bands that are attached to theframe at both ends of the bands. FIG. 3B is a perspective view of thefilter frame of FIG. 3A attached to a grill of a box fan, in accordancewith the present invention.

FIG. 4 is a perspective view of another embodiment of the presentinvention including a filter frame attachable to a grill of a box fanusing elongated bolts, washers and wing nuts.

FIG. 5 is a perspective view of another embodiment of the presentinvention including a filter frame attachable to a grill of a box fanusing a threaded fastener and bolt.

FIGS. 6A and 6B are perspective views of another embodiment of thepresent invention. FIG. 6A is a perspective view of a standard cable tieand FIG. 6B is a perspective view of a filter frame attachable to agrill of a box fan using the standard cable tie of FIG. 6A, inaccordance with the present invention.

FIG. 7 is a perspective view of another embodiment of the presentinvention, in which the filter frame includes first and second sidemembers and no base member, and in which a foam pad is applied betweenthe frame and the fan body, in accordance with the present invention.

FIG. 8 is a perspective view of another embodiment of the presentinvention, in which the filter frame includes a widened channel that isadapted to receive both a universal filter and a HEPA-standard filter,in accordance with the present invention.

FIG. 9 is a close-up perspective view of a side member of the filterframe of FIGS. 7 and 8, including a channel stop at an end of thechannel, in accordance with the present invention.

FIGS. 10A and 10B are illustrations of another embodiment of the presentinvention. FIG. 10A is a front view of another embodiment of a filterframe formed in a mold process. FIG. 10B is a close-up perspective viewof a side edge of the filter frame of FIG. 10A.

FIGS. 11A, 11B, 11C and 11D are perspective views of another embodimentof the present invention. FIG. 11A is a perspective view of anotherembodiment of the molded filter frame of FIGS. 10A and 10B includingspring-loaded hooks for latching the filter frame to the grill of thefan. FIG. 11B is a close-up perspective view of a top corner of a rearface of the filter frame of FIG. 11A including the spring-loaded hooks.FIG. 11C is a close-up perspective view of a corner of a front face ofthe filter frame of FIG. 11A. FIG. 11D is a perspective view of thefilter frame of FIG. 11A mounted to a fan body.

FIGS. 12A-12C are perspective views of another embodiment of the presentinvention. FIG. 12A is a perspective view of another embodiment of themolded filter frame of FIGS. 10A and 10B including spring-loaded hooksfor latching the filter frame to the grill of the fan. FIG. 12B is aclose-up perspective view of a bottom corner of a rear face of thefilter frame of FIG. 12A including spring-loaded hooks. FIG. 12C is aclose-up perspective view of a top corner of a rear face of the filterframe of FIG. 12A.

FIGS. 13A-13E are perspective views of another embodiment of the presentinvention. FIG. 13A is an embodiment of the filter frame integral with afan grill attached to the fan body. FIG. 13B is a close-up perspectiveview of a side edge of the filter frame and the fan grill of FIG. 13A.FIG. 13C is an exploded perspective view of an embodiment of a box fanand fan grill with an integral filter frame. FIGS. 13D and 13E areassembled views of alternative embodiments of the fan grill with anintegrated filter frame.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1A is a perspective view of a filter frame 32 adapted to be securedto a body of a portable fan, such as a standard box fan, using elasticbands 33. A filter frame 32 is configured to include frame channels in aU-shaped arrangement having first and second side members 42 and a basemember 44. Cross-members 37 are coupled between opposite corners of theframe to provide lateral rigidity. The first and second side members 42include longitudinal channels 46 that are spaced apart and opposed, andthat provide a slot or seat for receiving side edges of an insertedfilter. The base member 44 extends between the first and second sidemembers 42 and includes a similar longitudinal channel 47 that isaligned with the longitudinal channels 46 of the side members 42 forreceiving a bottom edge of an inserted filter. Top portions of the sidemember frame channels 46 are open to provide an insertion and removallocation for the filter. The side members 42, base member 44, and crossmembers 37 of the filter frame 32 comprise extruded aluminum, plastic,graphite, or other suitable light-weight and durable material that ismolded or otherwise machined or formed. The members may be riveted,bolted, welded, or otherwise coupled together, or may be molded andformed as a complete unit.

Elastic bands 33 are permanently attached, at first ends, to a top rightcorner, bottom right corner, top left corner and bottom left corner ofthe filter frame 32. The elastic bands 33 are, for example, riveted,bolted, tied, or otherwise attached to the frame 32. The elastic bands33 further include hooks 34, or other clasping mechanisms, at a secondend. The elastic bands 33 comprise, for example, bungy cords, elasticribbons, or straps. In alternative embodiments, the hooks 34 on theelastic bands 33 are tied, coupled to, or integral with, the elasticbands 33 at their second ends. The hooks 34 are preferably coated with asoft plastic or rubber material to avoid scratching the fan chassis.

The frame 32 is preferably sized to closely match, and cover, astandard-sized fan grill at an input or output face of the fan, so thata substantial amount of air flow induced by the fan passes through theinserted filter. The side members 42, base member 44 and cross members37 of the filter frame are preferably sized to have a narrow profile soas to reduce the restriction of air flow. In one embodiment, the framechannels 46 are spaced apart a suitable distance, and formed of a depth,so as to accommodate a general purpose forced-air filter, for example ¾″by 20″ by 20″ in size. The 20″ by 20″ filter profile matches well with avariety of box fan sizes. Therefore, the depth of the channel 46 in thisexample is made to be slightly larger than ¾″ and the side members 42are spaced apart slightly more than 20″ in order to accommodate aninserted filter. Other filter sizes and other channel depths can also beapplied to accommodate fans and filters of varying dimensions, and areequally applicable to the present invention.

FIG. 1B is a perspective view of the filter frame 32 of FIG. 1A attachedto a box fan 31. The frame 32 is positioned at a first face 52 of thebox fan 31 and the elastic bands 33 are pulled about the sides of thefan chassis to a second face 54 of the fan 31. The hooks 34 are claspedto an existing feature of the box fan 31, for example a grate of a grill71 on the second face 54 of the fan. Tension in the stretched elasticbands 33 retains the filter frame 32 against the fan body 31. Althoughthe above described embodiment illustrates multiple bands 33 with hooks34 at each of the first and second side members 42, each side member 42can optionally include a single elastic band/hook, depending on theapplication. The elastic band configuration is equally applicable to anyof the filter frame embodiments described herein.

FIGS. 2A-D are perspective views of another embodiment of the presentinvention. FIG. 2A is a perspective view of an elastic band 38 having ahook 34 at a proximal end and an array of holes 50 at a distal end. Inone embodiment, the holes 50 are spaced ¾″ apart and are distributedlongitudinally along the end of the elastic band 38.

FIG. 2B is a perspective view of the elastic bands 38 of FIG. 2A hookedonto a grate of a grill 71 at a second face 54 of the box fan 31 at topright, bottom right, top left, and bottom left positions by the hooks34.

FIG. 2C is a perspective view of a filter frame 32 of a constructiongenerally similar to that described above in FIG. 1A. In thisembodiment, however, the elastic bands are not permanently attached.Instead, the filter frame 32 includes mounting knobs 41 that extend fromthe body of the frame 32 at top right, bottom right, top left and bottomleft corners of the frame. The mounting knobs 41 have relatively narrownecks with relatively wide heads, such that when the holes 50 at thedistal ends of the elastic bands 38, held in place at their proximalends by the hooks 34, are pulled over the knobs 41, the elastic bands 38are seated in position by the heads of the knobs 41.

FIG. 2D is a perspective view of the filter frame of FIG. 2C attached tothe box fan 31 of FIG. 2B by the elastic bands 38 of FIG. 2A. The holes50 of the elastic bands 38 are pulled over the mounting knobs 41 offilter frame 32 to secure the four corners of the filter frame 32 to thebox fan 31. Tension in the stretched elastic bands 38 retains the filterframe 32 against the body of the fan 31. Different holes 50 of theelastic bands 38 can be used to accommodate fan bodies 31 of differentthicknesses, and to accommodate a range of different positions forhooking the hooks 34 on the grill, or other feature, of the fan. Themounting knob/elastic band configuration can be applied to any of theframe embodiments described herein.

In another embodiment, each of the upper and lower pairs of elasticbands 33, 38 of the FIG. 1 and FIG. 2 embodiments described above can bedimensioned in length so that their hooks 34, or other claspingfeatures, can be coupled to each other to form one large band thatextends about the fan chassis to secure the filter frame 32 in place.

FIGS. 3A and 3B are perspective views of another embodiment of thepresent invention. FIG. 3A is a perspective view of a filter frame 32attachable to a box fan using elastic bands. In this embodiment, theelastic bands 25 a, 25 b are permanently coupled to the opposed firstand second side members 42 of the filter frame 32. A first elastic band25 a extends across the filter frame 32 from the top right corner to thetop left corner, and a second elastic band 25 b extends from the bottomright corner to the bottom left corner of the filter frame 32. Whenmounting the frame 32 to a box fan 31, as shown in FIG. 3B, the firstelastic band 25 a is pulled over the top of the box fan 31, and thesecond elastic band 25 b is pulled over the bottom of the box fan 31.Alternatively, the first and second elastic bands 25 a, 25 b can both bepulled over the top or the bottom of the box fan 31 and positioned intoplace. The tension in the elastic bands 25 a, 25 b retains the filterframe 32 against the box fan 31. In alternative embodiments, one end, orboth ends, of the elastic bands 25 a, 25 b are removable from the filterframe 32, for example using the holes and knobs combination describedabove with reference to FIGS. 2A-2D. This elastic band configuration isequally applicable to any of the filter frame embodiments describedherein.

FIG. 4 is a perspective view of another embodiment of the presentinvention including a filter frame attachable to a grill of a box fan 31using elongated bolts 53, washers 65 and wing nuts 64. In thisembodiment, the filter frame 32 is secured to the fan chassis 31 byelongated bolts 53 that extend through the fan 31. For example, thebolts 53 can be configured to be of a length so as to extend throughgrate openings that exist in both the front and rear grills 71 of thefan 31. Holes 62 are included in the frame 32 at the cross members 37 orside members 42 to receive the bolts 53. The holes 62 are preferablyelongated to allow for play in positioning the frame 32 relative to thefan body 31, so that the frame 32 is compatible with different fan grillconfigurations. The elongated bolts 53 are secured to the filter frame32 and fan 31 with washers 65 and wing nuts 64, which, when tensioned,retain the filter frame 32 against the body of the fan 31. The holes 62and bolts 53 are configured to align with the four corners of the fangrill, so as to avoid interference with fan operation. The bolts 53 arepreferably of a length so as to accommodate fan bodies of differentdepths. Tightening the wing nuts 64 creates a tension in the bolts thatretains the filter frame 32 against the fan body 31. The wing nuts 64and bolts 53 are readily mountable by an individual without the need fortools. The elongated bolt and wing nut mounting configuration can beapplied to any of the filter frame embodiments described herein.

FIG. 5 is a perspective view of another embodiment of the presentinvention including a filter frame 32 attachable to a grill of a box fan31 using fasteners 18. The fasteners 18 are bolted to the frame 32, forexample at cross-members 37 or side members 42. Holes 67 are included inthe frame 32 to receive the bolts 66. The holes 67 are preferablyelongated to allow for play in positioning the frame 32 relative to thefan body 31, so that the frame 32 is compatible with different fan grillconfigurations. A fastener 18 is inserted into a fan grill 71 in ahorizontal position between cross members of the rear or front fan grill71 of the fan, and is then rotated to a vertical position and tightenedin place with bolt 66 to affix the filter frame 32 to the fan 31. Thefastener 18 is sized to accommodate a range of fan grill configurations.The fastener 18 may include a threaded hole 68 to receive the bolt 66,or, optionally washers and nuts may be employed. Tightening the bolt 66relative to the fastener 68 provides tension which holds the frame 32against the box fan 31. The fastener configuration described in FIG. 5is equally applicable to any of the filter frame embodiments describedherein.

FIGS. 6A and 6B are perspective views of another embodiment of thepresent invention. In this embodiment, a plurality of standard cableties 69 as shown in FIG. 6A are used to mount the filter frame 32 to thegrill of the box fan 31 as shown in FIG. 6B. Holes 67, for exampleelongated holes, are formed in the cross members 37 or side members 42of the frame 32, and standard cable ties 69 are wrapped around the holes67 and a grate of the fan grill 71, and tightened, to secure the filterframe 32 against the fan grill 71. The excess portion of the cable tie20 is preferably cut off to avoid vibration during fan operation, and toavoid interference with an inserted filter. The cable ties 69 aretightened so as to create sufficient tension to secure the filter frame32 to the box fan 31. The cable tie configuration described in FIG. 6 isequally applicable to any of the filter frame embodiments describedherein.

FIG. 7 is a perspective view of another embodiment of the presentinvention. In this embodiment, the filter frame 32 includes first andsecond side members 42A, 42B and no base member. In this embodiment,rather than including a base member 44 as shown in the above embodimentsof FIGS. 1-6, the side members 42A, 42B of the present embodiment eachinclude a channel stop 106 at or near a distal end of the channel 46, inorder to limit or stop the insertion of a filter 100, as shown in FIG.9. The channel stop 106 can take the form of a solid face, a meshsurface, a peg, a dimple, or any suitable means for restricting downwardmovement of the filter 100 in the channel 46. The channel stop structurecan be applied to any of the filter frame embodiments described herein.

Further, in the embodiment of FIG. 7, a single pair of elastic bands 33and hooks 34 is included for mounting the filter frame 32 to the fanbody. A single pair of elastic bands 33 can be equally as effective as adouble pair as shown above in FIGS. 1, 2 and 3 for securing the frame 32to the fan body 31, depending on the application.

In addition, the embodiment of FIG. 7 includes an optional foam pad 108or gasket that is applied between the filter frame 32 and the fan body31. The foam pad 108 includes an opening 109 that allows free passage ofair, the opening 109 being about as large as the cross-section of thevolume of air that the fan is designed to push, so as not to restrictair flow. The foam pad 108 prevents air from entering the fan at a gapthat may be present between the filter frame 32 and the surface of thefan body 31. In this manner, the foam pad 108 causes more of the airthat is pushed by the fan to pass through the filter 100, therebyimproving the air cleaning efficiency of the system. Further, if thefoam pad 108 is cut to closely match the diameter of the fan blades,back draft in the corners of the box fan can be prevented. By preventingthe back draft in the box fan, an air flow can be created that flows ina single direction, thus making the fan more efficient in configurationsin which negative air pressure is created. The foam pad configurationcan be applied to any of the filter frame embodiments described herein.

FIG. 8 is a perspective view of another embodiment of the presentinvention. In this embodiment, the filter frame 32 includes a widenedchannel 46. The channel 46 is widened so as to accommodate both auniversal pre-filter 100 and a High Efficiency Particulate Air (HEM)type filter 102, in accordance with the present invention. The widenedchannel 46, in one embodiment, is a single channel that is of a width soas to accommodate both the universal pre-filter 100 and the HEPA filteradjacent each other. In another embodiment, the channel 46 may comprisea double channel that includes a central rail for partitioning first andsecond slots of the channel. In this manner, either, or both, filters100, 102 can be properly seated in designated slots of the channel 46.This widened channel configuration can be applied to any of the filterframe embodiments described herein.

Further, the embodiment of FIG. 8 includes pegs or bumps 104 that extendin a direction transverse to the longitudinal direction of the filterchannels from a face of each side member 42A, 42B or optionally from thecross members 37 or other portion of the frame 32. The pegs 104 areadapted to rest in an opening between adjacent grates of the fan grill71. The pegs 104 prevent the frame 32 from shifting or sliding in adownward direction when the frame 32 is mounted to the fan and preventmovement of the frame 32 relative to the fan as a result of vibration.In one embodiment, the pegs 104 are approximately ¼″ in length. The pegconfiguration is equally applicable to any of the filter frameembodiments described herein.

FIGS. 10A and 10B are illustrations of another embodiment of the presentinvention. FIG. 10A is a front view of another embodiment of a filterframe 74 that is suitable for formation in a mold process. Thisembodiment of the filter frame 74 includes first and second spaced-apartand opposing side channels 46 that are defined by a plurality of sidechannel tabs 76. The channels 46 provide a guide for receiving oppositeedges of an inserted filter. The frame 74 further includes cross-members37 that are coupled between opposite corners of the frame to providelateral rigidity. The lowest side tabs 76 of the channels 46 areprovided with bottom surfaces 78 that operate as a stop to limit thevertical position of the inserted filter. A top portion 89 of the frame74 is open to provide an insertion and removal location for the filter.The left and right edges of the frame include mounts 80, each comprisingan opening for attaching elastic bands, bolts and nuts, hooks, or otherfastening means to secure the filter frame 74 to the fan body, forexample in the manner of the other embodiments described herein.

FIG. 10B is a close-up perspective view of a side edge of the filterframe 74 of FIG. 10A. In this view it can be seen that a void 82 isprovided in the channel 46 under each respective side tab 76. In thismanner, the filter frame of the present embodiment can be formed in astraight-pull injection molding process, such that there are nosecondary movements required inside the mold during the molding process.An extension formed in the lower mold passes through a region where thevoids 82 are to be formed. When the upper and lower molds are inposition, material is injected, and the extension formed in the lowermold defines a lower part of the side tabs 76. When the mold isretracted, the extensions pass through the voids that are formed belowthe tabs, so as to form the frame in a straight-pull injection moldingprocess. In this embodiment, the side edges, side tabs 76, bottomsurfaces 78, notches 80, and cross members 37 of the filter frame 74comprise aluminum, plastic, composite, graphite, or other suitablelight-weight and durable material that can be formed in a moldingprocess. The molded filter frame of FIG. 10A formed in the straight-pullinjection molding process is equally applicable to any of the filterframe embodiments described herein.

FIGS. 11A, 11B, 11C and 11D are perspective views of another embodimentof the present invention. FIG. 11A is a perspective view of anotherembodiment of the molded filter frame of FIGS. 10A and 10B includingspring-loaded or spring-biased hooks for attaching the frame directly toa grill of the fan. FIG. 11B is a close-up perspective view of a topcorner of a rear face of the filter frame 74 of FIG. 11A. FIG. 11C is aclose-up view of a corner of a front face of the filter frame 74 of FIG.11A. In this embodiment, springs 92 are attached to the top corners ofthe filter frame 74. A first end of each spring 92 is attached to thefilter frame 74 at a spring seat 90, for example in a press-fitrelationship, or alternatively by a fastener or adhesive. A second endof each spring 92 extends through a corresponding hole 96 at each topcorner of the filter frame. In this embodiment, the second ends of thesprings 92 include integral hooks 94. The hooks 94 are adapted to securethe filter frame 74 to the grate of the fan grill, and are shaped tointerlock with features of common fan grills, for example rectangularopenings and grates of the fan grill. The hooks 94 extend in a directiontransverse to the longitudinal axes 101 of the channels 46, and fingers94A at the ends of the hooks are configured to be inserted through anaperture in the fan grill and to latch a surface of the fan grill, forexample an inner surface of a grate of the fan grill. In this manner, atop portion 89 of the filter frame 74 is removably secured to the fanbody at the fan grill by a downward force of the springs 92. The filterframe 74 further includes lower tabs 93 at a bottom region of the filterframe 74. The lower tabs 93 can be integral with the filter frame 74 andcan be molded on or otherwise attached to the filter frame 74. The lowertabs 93 are adapted to secure the filter frame 74 to the fan grill andare shaped to extend from the filter frame 74 in a direction transverseto the longitudinal axes 101 of the channels 46 of the filter frame 74so as to interlock with a feature of a common fan grill, for example theopenings and grates of the fan grill. Lips, or other interlockingfeatures, that extend from the lower tabs 93 are adapted to latch withthe inner surfaces of the grates of the fan grill, through openings inthe grate. The lower tabs 93 operate to counteract the downward force ofthe springs 92. The tension between the springs 92 and the lower tabs 93operates to retain the filter frame against the fan body 31. The presentspring-loaded hook and tab configuration is applicable to any of thefilter frame embodiments described herein. FIG. 11D is a perspectiveview of the filter frame 74 of FIG. 11A mounted to a fan body 31. Hooks94 are inserted through apertures 75 of the fan grill and interlockedwith the cross-members of the grate 73 of the fan grill 71. Lower tabs93 extend through apertures 75 of the fan grill and are latched with theinner surfaces of the grates 73 of the fan grill 71.

FIGS. 12A, 12B and 12C are perspective views of another embodiment ofthe present invention. FIG. 12A is a perspective view of anotherembodiment of the molded filter frame 74 of FIGS. 10A and 10B includingspring-loaded or spring-biased hooks. FIG. 12B is a close-up perspectiveview of a bottom corner of a rear face of the filter frame 74 of FIG.12A. FIG. 12C is a close-up of a top corner of a rear face of the filterframe 74 of FIG. 12A. This embodiment is similar in structure and formto the embodiment of FIG. 11 above, except that in this embodiment, thetabs 93 are at an upper portion of the filter frame 74 and the springs92 are at lower portion of the filter frame 74. In the presentembodiment, the tabs 93 include fingers 99 that are oriented in adownward direction, and therefore, when inserted in a grate of a fangrill, through an opening in the grate, the tabs 93 bear the weight ofthe filter frame 74 and mounted filter. The springs 92 includeupward-oriented hooks which, when engaged with the grate of the fangrill, operate to hold the filter frame 74 in place against the grill.Mounts 80 are also included at far left and right edges of the filterframe 74 for further mounting the frame to the fan body using optionalelastic bands, as described above. The present embodiment can be appliedto any of the filter frame embodiments described herein.

FIGS. 13A-13E are perspective views of another embodiment of the presentinvention in which a filter frame is integral with a fan grill of thefan body. Referring to FIG. 13A, the grill 111 includes a latticed gratethat includes cross members and openings. The grill 111 of the box fan31 includes multiple side tabs 110 that form first and second sidechannels 118 and multiple bottom tabs 112 that form a base channel 119.The side tabs 110 operate as retaining members for an inserted filter,and extend outwardly from the grill 111 surface in a directiontransverse to a longitudinal axis of the first and second side channels118, and then in an inward direction toward a center of the grill. Thebottom tabs 112 operate as stops for an inserted filter and, in theembodiment shown in FIG. 13A, extend from the surface of the fan grill111 in a manner similar to the side tabs 110. The side and bottom tabs110, 112 are molded with the grill 111 of the box fan 31, such that thefilter frame and the grill 111 of the box fan are unitary. The side tabs110 and bottom tabs 112 in combination provide a slot or seat forsecuring an inserted filter to the grill 111 of the box fan 31. The sidechannels 118 are spaced apart, as described above, and are dimensionedto provide a seat for receiving opposite edges of an inserted filter.The bottom tabs 112 operate as a stop at a bottom portion of the slot toprovide a location for vertical positioning of the inserted filter. Atop portion 89 of the slot provided by the filter frame is open toprovide an insertion and removal location for the filter. With referenceto FIG. 13B, in an alternative embodiment, the side tabs 110 can bemolded directly to the grill 111. The side tabs 110 each include a firstportion 110 a that extends in an outward direction from the surface ofthe fan grill and a second portion 110 b that extends from the firstportion 110 a in a direction toward a central region of the fan, forexample L-shaped, so as to form a channel 118. The tabs 110, 112 andunderlying voids 111 a are preferably shaped so as to accommodate astraight-pull injection molding process for forming the grill 111, asdescribed above. FIG. 13C is an exploded perspective view of anembodiment of a box fan and fan grill including an integral filterframe. The box fan has fan blades 117 and a motor for operating the fanblades 117. A fan chassis surrounds the fan blades and motor. The fangrill shields the fan blades 117 and allows for air movement through thefan. The filter frame may be integral with the front grill, the reargrill, or both the front and rear grills of the box fan 31.

With reference to FIG. 13D, the side tabs 110 are integral with thegrill 111. In this embodiment, the lowest side tabs 110 of the channels118 are provided with bottom surfaces 114 that operate as a stop toprevent further insertion of the filter. Therefore, in this embodiment,additional bottom tabs are not necessary.

FIG. 13E is an assembled view of another embodiment of the grill 111with an integrated filter frame including single, elongated, left andright side tabs 116 and a single bottom tab 120, rather than multipletabs as shown above.

In one embodiment of a method of mounting a filter to a fan 31, themethod includes coupling the filter frame 32, 74 that has opposed firstand second side channels 46, each of the first and second side channels46 having a longitudinal axis, to a grill 71 of a fan by couplers, forexample elongated bolts 53 and wing nuts 64, fasteners 18, cable ties69, hooks 94 or tabs 93, extending from the frame body in a directiontransverse to the longitudinal axes of the first and second sidechannels 46. The couplers engage a grate 73 of the grill 71 through anopening 75 in the grate. The first and second side channels 46 define aslot for insertion of an air filter. The slot has an upper portion 89that allows for insertion and removal of an air filter, and a lower endthat includes a stop 44, 106, 78, for restricting further movement of aninserted air filter. An air filter 100, 102 is inserted into an upperend of the slot. Coupling the frame body to the grill of the fanoptionally further includes coupling the frame body to the grate 73 ofthe grill of the fan using at least one tab 93 extending from the framebody 32, 74. Further, coupling the frame body 32, 74 to the grill of thefan optionally further includes coupling the frame body to the grate 73of the grill of the fan using at least one hook 94 extending from theframe body 32, 74.

In another embodiment of a method of mounting a filter to a fan 31, themethod includes coupling a frame body 32, 74 having opposed first andsecond side channels 46 to a grill of a fan by at least one elastic band33, 38, 25 a, 25 b extending about a portion of a fan chassis so thatwhen installed, tension in the at least one elastic band 33, 38, 25 a,25 b operates to secure the frame body to the fan 31. The first andsecond channels 46 define a slot for insertion of an air filter. Theslot has an upper portion 89 that allows for insertion and removal of anair filter, and a lower end that includes a stop 44, 106, 78 forrestricting further movement of an inserted air filter. An air filter100, 102 is inserted into an upper end of the slot.

In another embodiment, a method for forming a grill 111 for a fan 31comprises forming a latticed grate including cross members and openingsand having an inner surface and an outer surface. The method furtherincludes forming retaining members 110, 116 extending from the outersurface of the grate in a direction transverse to the outer surface atfirst and second outer regions of the grill 111 to define opposed firstand second side channels 118. The first and second side channels 118define a slot for insertion of an air filter. The slot has an upper endthat allows for insertion and removal of an air filter, and a lower endthat includes a stop 112, 114, 120 for restricting further movement ofan inserted air filter. The grill 111 is mounted to a fan chassis.

In this manner, the present invention provides a filter frame that canbe readily mounted to and removed from a chassis of a fan, withoutcausing permanent disfigurement of the fan body. In addition, thepresent invention provides a filter frame that is integrated into thegrill of the frame, to further ease the application of a filter to afan.

While this invention has been particularly shown and described withreferences to preferred embodiments thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade herein without departing from the spirit and scope of the inventionas defined by the appended claims.

The invention claimed is:
 1. A fan, comprising: fan blades; a motor thatoperates the fan blades; a fan body comprising a fan chassis thatsurrounds the motor and fan blades and front and rear grills that shieldthe fan blades and allow for air movement through the fan, each of thefront and rear grills comprising a lattice grate; and a plurality ofchannel tabs that define a channel, wherein the plurality of channeltabs extend in an outward direction from an outer surface of the fanbody, wherein the plurality of channel tabs comprise a plurality of sidechannel tabs that define first and second opposing side channels and atleast one lower channel tab that defines a lower side channel thatdefines a stop to limit a vertical position of an inserted filter. 2.The fan of claim 1, wherein a longitudinal axis of the lower sidechannel is perpendicular to longitudinal axes of the first and secondside channels.
 3. The fan of claim 1, wherein the plurality of sidechannel tabs comprise a first portion extending from the outer surfacein a direction transverse to the outer surface and a second portionextending from the first portion in a direction substantially parallelto the outer surface and toward a middle region of the fan body.
 4. Thefan of claim 1, wherein the plurality of channel tabs are L-shaped. 5.The fan of claim 1, wherein the plurality of channel tabs extend fromthe front and rear grills.
 6. A fan, comprising: fan blades; a motorthat operates the fan blades; a fan chassis that surrounds the motor andfan blades; front and rear grills that shield the fan blades and allowfor air movement through the fan, each of the front and rear grillscomprising a lattice grate; and a plurality of retaining members thatdefine a channel, wherein the plurality of retaining members extend inan outward direction from a surface of the lattice grate of at least oneof the front and rear grills, wherein the plurality of retaining memberscomprise a plurality of retaining members that define first and secondopposing side channels and at least one lower retaining member thatdefines a lower side channel that defines a stop to limit a verticalposition of an inserted filter.
 7. The fan of claim 6, wherein alongitudinal axes of the lower side channel is perpendicular tolongitudinal axis of the first and second side channels.
 8. The fan ofclaim 6, wherein the plurality of side channel retaining memberscomprise a first portion extending from the outer surface in a directiontransverse to the outer surface and a second portion extending from thefirst portion in a direction substantially parallel to the outer surfaceand toward a middle region of the lattice grate.
 9. The fan of claim 6,wherein the plurality of retaining members are L-shaped.